Production of active species in a common flowing post-discharge of an Ar-N₂plasma and an Ar-H₂-CH₄plasma

A common flowing post-discharge of an Ar-N 2 plasma and an Ar-H 2 -CH 4 plasma has been used to produce nitrogen and carbon atoms. The concentrations of the nitrogen and carbon atoms have been determined by NO titration and from measurement of the vibrational band intensities of the spectra emitted by the N+N and C+N chemiluminescent reactions. For plasmas created with microwave powers of 40-100 W and for total gas densities of 5*10 17 cm -3 typical values for the atom densities of 10 15 cm -3 for nitrogen and 10 11 -10 13 cm -3 for carbon are obtained after a residence time of 25 ms in the post-discharge.